Stop motion control device for knitting machines

ABSTRACT

Apparatus for controlling the operation of a knitting machine in response to the tension of the yarn comprising a crank member having a yarn guide fixed thereto, and being resiliently biased in one direction, the crank being reversible in response to a predetermined tension to operate control means for stopping the machine.

United States Patent 1 1 3,650,128

Ferda et a]. 1451 Mar. 21, 1972 [54] STOP MOTION CONTROL DEVICE FOR1,992,860 2/1935 Crawford ..66/161 KNITTING MACHINES 2,329,618 9/1943lngaiis ..66/161X 3,321,755 5/1967 Cooke ...66/163 ux 1 Inventors: JFerdl, y py J Kollckl, 3,379,037 4/1968 Antonevich.. ..66/163 both ofCzechoslovakia 3,390,553 7/1968 Mishcon ..66/161 [73] Assign: Em, zmdymmnnm smfimml 2,329,427 9/1943 Voseen" ...66/163 ux "mm MM I Ubm2,467,952 4/1949 Antonev1ch.. ..66/163 I 2,654,238 10/1953 Heyne..66/163 Czechoslovak1a [22] Filed: 15,1969 FOREIGN PATENTS ORAPPLICATIONS 390,134 1933 Great 811mm ..66/163 742,533 12/1955GreatBritain....

1,090,648 11/1967 Great Britain ..66/163 [301 Foreign ApplicationPriority Data P Ex RobertR.M ck Aug. 16,1968 Czechoslovakia ..5935/68Low 521 u.s.c1 ..66/163,66/161,200/61.13 [57] ABSTRACT 51 1111.0...11041135/10 [58] Field ofSearch ..66/163, l61;200/61.13 Apparatusforcomwllms the 91291199911 ofakmmns machme in response to the tensionof the yarn comprising a crank [56] Rdennm Cited member having a yarnguide fixed thereto, and being resiliently biased in one direction, thecrank being reversible UNITED STATES PATENTS in response to apredetermined tension to operate control means for stopping the machine.

1,358,483 11/1920 Wachsman ..66/161 1,778,097 10/1930 Wachsman ..66/161X 6Claims,5Drawing Figures sror MOTION coNraoLpavrca roa xNrmNc MACHINESThe present invention relates to apparatus for feeding yam to a knittingmachine and in particular to apparatus for controlling the operation ofsaid machine in dependence upon the tension on said yarn.

As is well known yarn is fed to the thread guides in an automaticknitting machine from individual spools mounted on a frame or creel. Toinsure proper and continued operation of the machine it is provided withone or more control devices responsive to yarn tension and continuity.One such device comprises a stationary arm carrying a forked yarn guideand a pair of movable arms 'one of which is adjustably rotatable whilethe other is a freely pivoted counterweighted arm. The rotatable andcounterweighted arms-are secured to independent shafts mounted within acarrying sleeve adapted to have fixed thereto the stationary guide arm.The rotatable arm is spring mounted, and is adjustable to provide afixed tension on the yarn as the yarn is fed to the stationary arm whilethe pivoted counterweighted arm is freely movable in response to thetension of the yarn. Yarn is passed over each of the rotatable andpivotal arms serially as it is fed to the stationary arm from whence itis fed to the thread guides. The rotatable arm and the pivotedcounterweighted arm and the carrying sleeve within which the shafts aremounted are provided with cooperating electrical contact members. Theelectrical contactmembers are connected to various machine controlelements in a manner whereby movement of the pivoted counterweightedarm, either asva result of excessive or insufficient tension, ormovement of the rotatable arm, as a result of yarn breakage, causes theknitting machine to stop operation. Thus it will be observed that theknitting machine can be controlled in its operation in response to theyarn tension and yarn continuity.

In general all known yarn tension and yarn continuity devices operate inthe same manner by detecting independently the tensionof the yarn andthe yarn continuity. The major disadvantage of these devices consistsinthat the conventional apparatus is very sensitive to even minorchanges in yarn tension which as is well known may occur from improperformation of the yarn diameter, or the winding of the yarn upon thebobbins as well as a number of other factors none of which are bythemselves sufficiently serious to warrant the stopping of the machine.Consequently the knitting machine is often stopped for noapparentreasomlt will be appreciated that the stoppage of the knittingmachine requires that the operator determine-.the cause of the stoppage,inspect the work product as well as the yarn and then restart themachine. This operation is particularly troublesome when there is infact no good reason for the machine to have been stopped in the firstplace. In an effort to overcome this inconvenience, the tension guide isoften set at a limit which is beyond the tensile strength of the yarn.Consequently the yarn breaks before the machine is stopped. This stateof affairs is even more serious than the prior described disadvantage.

It is an object of the present invention to provide a mechanism by whichthe disadvantages inherent in the prior art devices can be overcome.

It is a particular object of the present invention to provide amechanism for controlling the knitting machine operation in response tothe tension of the yarn fed there through operable only upon the tensionreaching a predetermined limit.

It is a further object of the present invention to provide a controldevice for operating knitting machines which is adjustable and which maybe preset to specific yarn tension limits.

It is still another object to provide a tension control device to avoidyarn breakage.

According to the present invention there is provided in association withconventional knitting machine control means, a pivoted yarn guide fixedto a unidirectional spring loaded over-the-center crank. The crank isadjustably loaded so as to have a predetermined resiliency to thetension of the moving yarn and to be responsive instantly to excessivetension of the yarn as it passes over the guide. The crank beingthereafter adapted to close contacts with the machine control meanswhereby operation of the machine maybe stopped.

The forementioned objects and advantages as well as numerous others willbe seen from the following description wherein reference is .made to theappended drawings, in which:

FIG. 1 is a front elevation of a longitudinal section through the deviceof the present invention in operation;

FIG. 2 is a side elevation of the longitudinal section of FIG. 1 takenalong the lines A A of FIG. 1;

FIG. 3 is a view similar to FIG. 1 showing the device of the presentinvention operative in response to an excessively tensioned yarn;

FIG. 4 is an enlarged view of the electric contact portion of thepresent device;

FIG. Sis a diagram of the electric circuit of the present device.

Before turning to the specific description of the present invention itis necessary to note that the description herein is limited to thedevice for determining excessive tension of a yarn threadQThe structureof the knitting machineasa whole and the showing of yarn bobbins,creels, feed mechanisms,

. thread guides etc. is omitted from the present description. It is feltthat a description of thisrelated material is unnecessary since they arewell known in the prior art and to those skilled in the art and for'thesake of brevity the present description describes 'only those elementswhich are absolutely necessary for the understanding of the presentinvention.

Turning to FIGS. 1 through 3 the present device comprises a rectangularbox like body 1 having a hollow cavity 3 at its upper end, and a cover 2which may be secured thereto in any conventional manner. The body 1 ispreferably formed of nonconductive material while the 'cover 2 ispreferably formed of conductive or metallic material for reasons to beexplained later. Secured within the back wall of the body 1 and thecover 2 (as seen in FIG. 2) are coaxially opposed friction bearingmembers 4 and 5, respectively. The bearing member 4 may be made of nylonor other similar plastic material which is nonconductive while thebearing 5 is made of conductive material. Both bearing 4 and 5 are forcefit within recesses formed within the body and cover, respectively.Located within the body cavity 3 is a crank member 8 having extendingwing like arms 6 and 7 rotatably secured within the bearing members 4and 5, respectively. The crank member 8 is bifurcated in its centralsection to provide a forked shaped recess 9 through which istransversely mounted a wrist pin 10. The wing like arm 7 extendingthrough the lid 2 is elongated and is provided with a transverse hole inwhich is inserted a nonnally horizontally extending arm 11 of a yarnhook 12. The arm I2 is maintained in fixed position within the elongatedcrank arm 7 by a conventional screw member and the yarn hook 12 issmoothly formed and it is adapted to hold the yarn as the yarn is fed tothe knitting machine.

A rod 14 is freely secured to the wrist pin 10. The rod I4 is likewisefreely secured at its other end to a second wrist pin 15 which istransversely secured within the end of a piston member 16 mounted so asto be freely movable in a bore '40 formed within the lower solid portionof the body member 1. The piston 16 is provided with an axial recess, 17within which one end of a tension spring 18 is fixed. The bore 40 isthreaded at its outer end and is provided with a correspondinglythreaded knob 19 the face of which abuts against the lower end of thespring 18 thereby resiliently loading the piston 16. The loading of thepiston 16 (that is the action of the spring 18 on the piston 16) may beadjusted by turning the knob 19.

It is to be noted from FIG. 1 that the device is arranged so that withinpredetermined limits of tension on the yarn I3 the arm 11 will extendhorizontally from the body I and permit the thread 13 to be guidedendlessly over the hook 12. In this disposed to each other about thewrist pin 10 and resiliently biased in one direction to abut against oneof the interior walls of the cavity 3. On the wall opposite the normalabutment of the crank 8 and 14 there is located a pair of electricalterminal contacts 20 and 21. Contact 21 is provided with a resilientleaf spring 21a which extends over the contact 20 and is normally out ofelectrical contact therewith. Extending from contacts 20 and 21 areelectrical leads 22 and 23, respectively. As will be noted from FIG. 3should the yarn guide hook l2 and the arm 11 be depressed, as forexample by excessive tension on the thread 13 the crank 8 and extension'14 pivotin the direction of arrow S (FIG. 1) and reverse theirpositions to abut against the opposite wall of the cavity 3 and incontact with the contacts 20 and 21. In doing so the crank 8 andextension 14 force the leaf spring contact 21a into electricalconnection with the contact 20 thus completing the circuit source, forexample, or it may be the power source for the en- 7 stopped or startedas desired.

tire knitting machine if desired. The second outlet terminal of thetransformer 24 is also grounded as for example to the knitting machine.

The first terminal of the transformer 24 is connected, in addition tothe lamp 25, to a pair of switches 26 and 27, across which are connecteda resistor 29 and the terminal C ofa multiple terminal solenoid relay28. The coil 30 of the solenoid relay 28 is connected at one end to theground and at the other end between the resistor 29 and the cover 2. Ascan now be seen the cover 2 acts as a separate and distinct ground orcommon contact, labeled X in thedrawings to which one ormore of thecircuit components may be connected. It is' for this reason that cover 2should be metallic or otherwise conductive. It will be appreciated thatthe body 1 maybe conductive while the cover 2 nonconductive if desired.The remaining terminals A and B of the relay 28 are connected to variouspower line sources for motors etc. of the knittingmachine itself, sothat upon actuation of.the coil 30 the knitting machine may be Thedevice just described functions mechanically in the following manner: Ayarn 13 is withdrawn from a selected bobbin located on a creel (both ofwhich are not shown) and suspended over the hook 12 which ishorizontally disposed .in its normal operating position. The yarn 13 asit moves, being pulled from the bobbin by operation ofthe knittingmachine, exerts a force upon the hook l2 pivoting the arm 11 and thecrank 8 in the direction of arrow S (FIG. 1). The rate of turning ofresiliently biased crank 8 is of course controlled by operation of thespring loaded piston 16 which as noted previously has been preset to apredetermined tension level by adjustment of knob 19. The preadjustnientof thespring 18 provides a maximum force which can be exerted by theyarn 13 in the direction S upon the guiding arm 11. This maximum forceis determined differently for each knitting machine, the yarn beingprocessed and other similar well known operating factors. So long as theyarn 13 does not exert a force greaterthan the maximum force or tensionof the spring l8 the yarn continuesto be guided over the hook 12 whichremains in a substantially horizontal 'position, the crank 8 and pistonrod 14 .moving between a dead center position and its normal operatingposition as shown in FIG. 1. Should, however, the force on the yarnexceed the maximum predetermined limit set by the spring 18 as seen byyar'n 13 in FIG. 3, then the crank 8 and rod 14 move beyond the deadcenter position and instantaneouslyreverse their angular dispositionwithin the cavity 3. Thereupon the crank 8 abuts against the contact1211 and completes the contact between the electrical terminals 20 and21. In the course of the motion of the crank 8 from its normal operatingposition toitsieverse position as shown in FIG. 3 the arm 11, at whichend the hook 12 is provided, pivots downwardly from a substantiallyhorizontal position to acute angular position allowingthe yam'toifallfrom the hook 12. This pivoting'the arm "11, which permits the yarn tofall, prevents the breakage oft'he yarn dueto any increased tension onthe yarn itself.

Turning to FIG. 5 the electrical operation of the device is seen.Initially the control device is set by closing both switches 26 and 27thereby completing circuit between the transformer 24, the resistor 29and the coil 30 of the relay 28. On activation of the coil 30 the relaycontacts 28 shift (to the right as seen in the FIG. 5) so that contactis made from the transformer 24 through switch 26 through contact C ofthe relay 28 thence through the resistor 29 and into the coil 30 therebyholding the coil 30 in its inward or right hand position. Simultaneouslythe switch 27 may be released and left open, the solenoid relay 28 beingfixed in contact position, In contact position relay contacts A AND Bare operative to permit the knitting machine to operate. So long as theyarn 13 does not exceed its predetermined maximum tension, the circuitjust described remainsstable. However at the moment in which the crank 8mechanicallyreverses its position and closes the contacts 20 and 21 thecircuit governing the activation of the coil 30 is shorted from theresistor 29 to the cover 2 and its common conductive portion X"completing a circuit through the switch members 20 and 21, lead 23, lamp25 and the transformer 24..As this occurs the coil 30 is deactivated andautomatically reverses its position causing all the relay contacts A, Band C to break. As' contacts A and B break, the knitting machine iscaused to instantaneously stop. Simultaneously with the stopping of theknitting machine the lamp 25 becomes illuminated indicating to tooperator the fact that machine has stopped.

The knitting machine will remain stopped and will not automaticallyreturn to activeposition until the operator manually replaces the hookmember 12 and arm 11 to its upward horizontal position to therebyrelease-the crank-8 from the contacts 20 and 21. It will be noted fromFIG. 3 that the crank 8.is constantly held in its reverse position dueto the tension placed upon it by the spring 18: Therefore the manualreversal of the hook and arm members 11 and 12 provides an advantageoussafety feature in that the machine cannot be inadvertently restarted,without fixing the yarn. The reversal of the crank member8 does not,however, automatically rest the electrical components of the knittingmachine which must also be manually accomplished by the operator. Thisis done, by again depressing the switch 27 and closing the circuitbetween it and the relay coil 30 as described earlier. The relay coil 30on reactivation again shifts contacts 28 so that the circuit betweencontactsA, B and C with the motors of the knitting machine and theresistor 29, respectively, can be completed.

It will now be seen that the present invention'provides a simple buteffective and novel device for controlling the operation of a knittingmachine in response to yarn tensionflt "will be observed that momentaryfluctuations in yarn tensions do not effect a stoppage of the knittingmachine, nor does excessive tension result in yarn breakage.- The'deviceis highly adjust'able and clearly'operative in many applications andwith a variety of knitting machines and 'yarn. Any number of modifications andchanges will be readily apparent to those skilled in the artand it is therefore intended that the present disclosure be taken solelyas illustrative of the inventive concepts.

What we claim: y

1. Apparatus for controlling the operation of a knitting machine inresponse to the tension of a yarn fed thereto comprising a hollow walledbody, switch means mounted on one wall of said body, a unidirectionalover-the-center crank "member having a pair of opposed axial extendingarms 'pivotally'secured withinlsaid body to pivot about a fixed axis,

second position out of engagement with said switch,"a piston locatedwithin an axial bore in a wall of said body ofi'set from said one walland transverse to the pivot axis of said crank member, a rod pivotallyconnected at its ends to said crank member and said piston respectively,cooperating therewith to form an articulated connection between saidcrank member and said piston, a spring fixed to said piston within saidbore to apply a predetermined force to said piston to normally bias saidcrank member in said second position, a yarn guide fixed to said crankmember and extending outwardly of said body to receive a moving yarn,said guide being adapted to pivot said crank member in response to thetension on said yarn and to overcome the biasing of the crank member bysaid spring and piston, said crank member being moved to said firstposition in response to a predetermined level of tension exceeding thepredetermined force of said spring and means operative upon engagementof said crank member with said switch to effect the stoppage of saidknitting machine.

2. The apparatus according to claim 1 including a knob threaded in thepiston bore adapted to. turning to selectively adjust the strength ofthe spring to thereby vary the biasing of the crank member.

3. The apparatus according to claim 2, wherein the switch includes anormally open electric contact operably closed by the crank member onreversal thereof.

4. The apparatus according to claim 1 wherein the means operable toeffect stoppage of the machine includes a self holding relaydisconnected on operation of said electric contact, said relay havingcontacts forming a portion of the electric circuit of the knittingmachine.

5. The apparatus according to claim 4 including means for preventingresetting of said relay until return of the crank member to its normallybiased position.

6. The apparatus according to claim 5 wherein the body is formed of atleast two parts only one of which is conductive, which conductive partforms a portion of the electric circuit, at least one arm of the crankmember being secured within said nonconductive part.

* III 10R

1. Apparatus for controlling the operation of a knitting machine in response to the tension of a yarn fed thereto comprising a hollow walled body, switch means mounted on one wall of said body, a unidirectional over-the-center crank member having a pair of opposed axial extending arms pivotally secured within said body to pivot about a fixed axis, said crank member being pivotable about the axis of said arms between a first position in engagement with said switch and a second position out of engagement with said switch, a piston located within an axial bore in a wall of said body offset from said one wall and transverse to the pivot axis of said crank member, a rod pivotally connected at its ends to said crank member and said piston respectively, cooperating therewith to form an articulated connection between said crank member and said piston, a spring fixed to said piston within said bore to apply a predetermined force to said piston to normally bias said crank member in said second position, a yarn guide fixed to said crank member and extending outwardly of said body to receive a moving yarn, said guide being adapted to pivot said crank member in response to the tension on said yarn and to overcome the biasing of the crank member by said spring and piston, said crank member being moved to said first position in response to a predetermined level of tension exceeding the predetermined force of said spring and means operative upon engagement of said crank member with said switch to effect the stoppage of said knitting machine.
 2. The apparatus according to claim 1 including a knob threaded in the piston bore adapted to turning to selectively adjust the strength of the spring to thereby vary the biasing of the crank member.
 3. The apparatus according to claim 2, wherein the switch includes a normally open electric contact operably closed by the crank member on reversal thereof.
 4. The apparatus according to claim 1 wherein the means operable to effect stoppage of the machine includes a self holding relay disconnected on operation of said electric contact, said relay having contacts forming a portion of the electric circuit of the knitting machine.
 5. The apparatus according to claim 4 including means for preventing resetting of said relay until return of the crank member to its normally biased position.
 6. The apparatus according to claim 5 wherein the body is formed of at least two parts only one of which is conductive, which conductive part forms a portion of the electric circuit, at least one arm of the crank member being secured within said nonconductive part. 